The "citation_pdf_url" meta tag download link doesn't use https

[KevinVdV]

Describe the bug
When running angular on server side & having an apache in front of it to ensure https access the "citation_pdf_url" shows as http.

This leads to an issue where users are not able to download publication file(s) via links from Google Scholar in Google Chrome and Microsoft Edge browsers.

To Reproduce
Checkout the following url's:

• https://unsworks.unsw.edu.au/entities/publication/fd08fc25-48dc-40bc-b673-deb232f31faa
• https://demo7.dspace.org/entities/publication/1974d7d3-9648-4dbe-b083-56374f5314e4

Expected behavior
The "citation_pdf_url" should be in https if the server is running on https.

[artlowel]

The cause of this issue seems to be that the ServerHardRedirectService uses the protocol and the host of the incoming request to determine the origin. So if you're not using https on the angular server directly but instead put a different server in front of it and redirect internally over http this will be wrong.

I suggest adding an optional config property, to set the origin. If it's missing we fall back to the current code.

This can be done in 2 hours. Atmire would like to claim it.

[tdonohue]

@artlowel : Sounds good, I'll assign back to you for your team to work on.